The present invention relates to a mechanism for protecting against irregular insertion of a disk into, and detecting and correcting a misalignment of a disk within, a disk player and specifically to such disk players that measure displacement of the disk relative to a registration position and are therefore susceptible to cumulative error.
Disk players that use a door to close an insertion opening to prevent the admission of dust and/or irregular insertion of a new disk, are known. For example, Japanese Utility Model Examined Publication No. 63-43659, describes a door that covers an insertion opening in the front face of a disk player. A spring, keeps the door closed. A tray is used to move a single disk into and out of the disk player. The door swings to a closed position when the tray moves from an eject position, where it projects outside the player, into the player. The door opens outwardly when pushed by the ejecting tray. When the ejecting tray passes through the front opening, the door is pushed open, and the tray projects from the insertion opening.
In players such as described above, the tray projecting from the front panel keeps the door open. However, some players do not use a tray to carry the disk but receive the disk through a slot in the front of the player (a "slot-in" design). However, to implement a gate in a slot-in device, the disk itself would have to open the door. This has disadvantages in that it can cause damage to the disk and increase the power requirements of the transport system due to friction between the door and disk.